development of new sampling

7/30/2019 Development of new Sampling

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CHAPTER 5

DEVELOPMENT OF NEW PROCESS

5.1 Introduction

From the study conducted on existing process revels it has identified several things, important

are, the cycle time for the production of cub-frame and coolant channel are 1.75 Hrs/component

and 1.25 Hrs/component respectively, manual strain of the labors are more because marking time

more for the guarding and also the quality of the components produced in the existing process is

less and the cycle time can be reduced by adopting the following methods

(i) Modification of production process of cub-frame will results in decreases the cycle time and

inventory cost materials.

(ii) Modification of production process of coolant channel will results in decreases the cycle time

and inventory cost of the materials.

5.2 Cub-frame Production Process

Cub-frame manufactured at SMD is depicted in the Figure 5.1. The various operations involved

in the manufacturing of cub-frame are cutting, bending, welding and finishing. The sequences of

operations in cub-frame production process are depicted in Figure 5.2.

Raw materials for Cub-frame manufacturing: High carbon steel contains from 0.7 to 1.00%

C with manganese ranging from 0.5to 0.9% this steel commonly known as spring steels. These

steels are generally operated at very high stress and heat treated to obtain the maximum elastic

limits and fatigue resistance without becoming sufficient brittle to cause sudden failure inservices. Harden ability of spring steel is very important because only fully hardened spring have

the maximum resistance to take a permanent set (sagging).


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Figure 5.1 Finished Cub-frame


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Figure 5.2 Proposed Cub-frame Production Process

CNC Laser cutting

of Cub frame parts Bending of Cub

frame partsWelding of Cub

frame parts

Inspection of cubframe

Finishing of Cub

frame parts

C\T for

cutting=10min

C\T for

Bending15min

C\Tforw

elding=20min

C\T for Finishing=10min

C\T for

Inspection is

5min


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CNC Laser Cutting operation: FANUC- CO2 CNC laser cutting machine is used to cut the

sheet metal for the production of cub-frame components. Each cub-frame component consists of

cutting operations of different lengths and the total cutting involves 5875 mm in length. The laser

cutting operation is computer controlled which gives high production rates and also high

accuracy of 0.025 mm. The cycle time required for this operation is 10 min.

Bending operation: CNC bending is a process where cub-frame is bent to an angle using,

typically a V shaped punch and die. The sheet is placed between the punch and die which presses

down on the sheet. It provides a low cost method to product 3D shapes from 2D sheets and it is a

suitable for processing most ductile metals and primarily for sheet metal designs with one or

more bends. A large percentage of sheet metal parts are bent along some lines to get them into

the desired shape for use. The sheet metal part before it is bent is called a blank. The cycle time

required for this operation is 15 min.

Welding operation: Spot welding process is used for Cub-Frame welds in SMD and the

different parts of cub-frames are welded with the help of welding fixture. The cycle time


Finishing: Hand grinders are used for final finishing operation process for cub-frame,

accompanied by a certain amount of metal removal and high surface finishing. The cycle time


Inspection: Inspection is carried out to check for the required dimension on all the cub-frame

components, after the completion of all the above process. In case of any deviation in the

dimensions frames will be sent back for rework. If the required dimensions are achieved it will

further sent to the painting division. The cycle time for the inspection process is 5 min. Figure5.4. The cycle time analysis for the production of Cub-frame components are given the Table 5.1

and the graphs of cycle time verses processes are show in the Figure 5.5.


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5.2.1 Operating cycle time of cub-frame

Basically, there are five processes are involved in the production process of cub-frame Sheet

metal guarding for a CNC Machine centers. Cycle time presently used in all the production

processes were noted which are given in the Table 5.1. The cycle time required to complete one

component of cub-frame is 60 min/ 1.00 Hrs and bar chart of cycle time is depicted in Figure 5.3.

It is observed that the cycle time required for manual drilling and tapping operation is completely

eliminated and it is adopted with the laser cutting machine by taking the advantages of laser

cutting and high accuracy.

5.3 Coolant channel Production process in proposed method

Coolant channel manufactured at SMD is depicted in the Figure 5.4. The various operations

involved in the manufacturing of coolant channel are cutting, bending, welding and finishing.

The sequences of operations in Coolant channel production process are depicted in Figure 5.5.

Raw materials for Coolant channel manufacturing: High carbon steel contains from 0.7 to

1.00% C with manganese ranging from 0.5to 0.9% this steel commonly known as spring steels.

These steels are generally operated at very high stress and heat treated to obtain the maximum

elastic limits and fatigue resistance without becoming sufficient brittle to cause sudden failure in

services. Harden ability of spring steel is very important because only fully hardened spring have

the maximum resistance to take a permanent set (sagging).

CNC Laser Cutting operation: FANUC- CO2 CNC laser cutting machine is used to cut the

sheet metal for the production of Coolant channel components. Each Coolant channel component

consists of cutting operations of different lengths and the total cutting involves 1206 mm in

length. The laser cutting operation is computer controlled which gives high production rates and

also high accuracy of 0.025mm. The cycle time required for this operation is 5 min.


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Table 5.1 Cycle Time in Proposed Production Process for Cub-frame

Sl no Sequence of Operations Cycle Time in min Cycle per batch

1 CNC laser cutting Operation 10 min 1200 min

2 CNC bending Operation 15 min 1800 min

3 Welding Operation 20 min 2400 min

4 Finishing Operation 10 min 1200 min

5 Inspection Operation 5 min 600 min

Total Cycle Time for Cub frame 60 min/1 Hrs 7200 min/120 Hrs


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Figure 5.3 Proposed Process Cycle Time for Cub-frame

0

5

10

15

20

25

CT for

Laser

Cutting

CT for

Bending

CT for

Welding

CT for

Finishing

CT for

Inspection

CycleTimein

min

Processes

Cub-frame


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Figure 5.4 Photo Graph of Coolant Channel


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Figure 5.5 Proposed Process Flow Diagrams for Coolant Channel

CNC Laser cutting

operation

Bending of Coolant

channel parts

Welding of

Coolant channel

parts

Inspection of

Coolant channel

Finishing of

Coolant channel

CT for

cutting

=10min

CT for

Bending

= 15min

CTforWelding10min

CT for

Finishing

=5min

CT for

Inspection

=5min


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Bending operation: CNC Bending machines are used for bending operation Coolant channel

production involve any one bending operation. A large percentage of sheet metal parts are bent

along some lines to get them into the desired shape for use. The sheet metal part before it is bent

is called a blank. The cycle time required for this operation is 15 min.

Welding operation: Spot welding process is used for Coolant channel welds in this division

with the help of fixture. The cycle time required for this operation is 20 min to completely weld.

Finishing: Hand grinders are used for final finishing operation process of Coolant channel

accompanied by a certain amount of metal removal. The cycle time required for this operation is

5 min.

Inspection: Inspection is carried out to check for the required dimension on all the Cub-frame

components, after the completion of all the above process. In case of any deviation in the

dimensions frames will be sent back for rework. If the required dimensions are achieved it will

further sent to the painting division. The cycle time for the inspection process is 5 min.

5.3.1 Operating cycle time for coolant channel

Basically, there are five processes are involved in the production process of coolant channelsheet metal guarding for a CNC Machine centers. Cycle time presently used in all the production

processes were noted which are given in the Table 5.2. The cycle time required to complete one

component of coolant channel is 45 min/ 0.75 Hrs and bar chart of cycle time is depicted in

Figure 5.6. The flat piece is replaced by circular bush with the inner thread cut and the welding

length is reduced.


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Table 5.2 Cycle Time for Production Process for Coolant Channel

Sl no Sequence of Operations Cycle Time in min Cycle time per batch

1 CNC laser cutting Operation 10 min 1500 min

2 CNC bending Operation 15 min 2250 min

3 Welding Operation 10 min 1500 min

4 Finishing Operation 5 min 750 min

5 Inspection Operation 5 min 750 min

Total Cycle Time for Coolant channel 45 min/ 0.75 hrs 6750 min/112.5 Hrs


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Figure 5.6 Cycle Time of Proposed Production Process for Coolant Channel.

10

5

10

5 5

0

2

4

6

8

10

12

CT for laser

Cutting

CT for

Bending

CT

forWelding

CT

forFinishing

CT for

Inspection

CycleTimei

nmin

Processes

coolant channel


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5.4 Comparing the Cycle Time in Existing Process with the

Proposed Method of Cub-frame Production Process

Comparing the cycle time and manufacturing cost of the cub-frame process in SMD were carried

out, after incorporating the new production flow process and reported that there is a substantial

improvement in the cycle time and also in the manufacturing cost of the component, by

eliminating the drilling and tapping operation in the sheet metal division and the operation is

incorporated with the CNC laser machine and the details is depicted in the Figure 5.11. The

purpose of comparison of existing process with the new process development for the

manufacturing cost reduction in this process, 66% of the cost is reduced with the new process

and also the 45 min of cycle time is reduced, details of this as shown in the Table 5.7 and alsoproduct cost V/s batch size as shown in the Figure 5.12.

5.5 Comparing the Cycle Time in Existing Process with the

Proposed Method of Coolant channel

Comparing the cycle time and manufacturing cost of coolant channel assembly in ACE designers

Ltd were carried out, after incorporating the new production flow process and reported. There is

a substantial improvement in the cycle time and also in the manufacturing cost of the component,

details is depicted in the Figure 5.13 For the purpose of comparison of existing process with the

new process development for the manufacturing cost reduction in this process 55% of the cost is

reduced with the new process and also the 30 min of cycle time is reduced, details of this as

shown in the Table 5.9 and also product cost V/s batch size is depicted in the Figure 5.14 show

the cost comparison of Coolant channel the existing process consumes cost Rs 4050 and the new

process consumes cost Rs 2700 with the reduction of cycle time 20 min and the elimination of

the drilling time in the existing process of Coolant channel manufacturing and 60% of the cost is

reduced and monthly saving is Rs 2847 and the details of about this is as show in the table, the

table shows the elimination of flat piece welding length, drilling and threading operation by

incorporating the circular bush with inner thread, the cost of the bush is low compare to the flat

welding operation.


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Sl no OPERATIONS BEFORE AFTER

1 RAW MATERIAL COST 0.5

2 CUTTING LENGTH IN MTS 2.693

3 NO OF BENDS 2

4 GRINDING LENGTH

5 NO OF BUSHES 4

DRILL AND TAPPING TIME IN Min 45 MIN 0.0

1 LASER CUTTING COST

Rs 88.00

Rs 37.20

2 RAW MATERIAL COST Rs 22

3 BENDING COST Rs. 4.00

4 WELDING COST Rs. 0.00

5 LABOUR COST Rs. 0.00

6 BUSH COST Rs. 10.00

7LABOUR COST PER DRILL AND

TAP WITH SUITINGS

Rs 48 0

TOTAL COST IN Rs. 136.1 74.0

TOTAL SAVING PER COMPONENT Rs. 62.10

NO. OF COMPONENTS PER MONTH 120 COMPONENTS

SAVING PER MONTH Rs. 7,452

SAVING PER YEAR Rs. 89,424

Table 5.3 Cost comparison as per the company standards for Cub-frame production


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5.7 Cycle Time Comparison for Cub-frame Production Process

5.8 Batch Size Cost Comparison for Cub-frame Production Process

10

45

1520

105

10

0

15

20

10

5

05

10152025303540

4550

CycleTimeinmi

n

Processes

Cycle TimeComparision for Cub-

Frame

Existing method of Cub

frame

Proposed method of Cub

frame Manufacturing

2722

5444

8166

10888

13610

16332

1480

2960

4440

5920

7400

8880

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20 40 60 80 100 120

ProductcostinRs

Batch size

Cost Comparision for Cub-frame

Cub frame before

Cub frame after


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OPERATIONS FLAT WELD RsBUSH WELD Rs

Sl No

1 RATE/PIECE 7.6 7.6 5.2 5.2

2WELD LENGTHIN MTS

52 5.2 25.12 2.5

3 DRILL TIME MIN 30 Min 14 0 0

Total 27 Total 8

SAVING PER COMPONENT Rs 19

NO. OF COMPONENTS PER MONTH 150 COMPONENTS

SAVING PER MONTH Rs 2,847

PER YEAR SAVINGS Rs 34,158

Table 5.4 Cost comparison as per the company standards for Coolant channel Production


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5.9 Cycle Time Comparison for Coolant channel Production Process

5.10 Batch size Cost Comparison for Coolant channel Production Process

10

15

10

30

5 5

10

5

10

0

5 5

0

5

10

15

20

25

30

35

Cycle

timeinmin

Production process

Existing method ofCoolant channel

Manufacturing

Proposed method of

Coolant channel

manufacturing

810

1620

2430

3240

4050

540

1080

1620

2160

2700

0

500

1000

1500

2000

2500

3000

3500

4000

4500

30 60 90 120 150

ProductcostinRs

Batch size

Cost comparision for Cub-frame

Coolant channel before

Coolant channel after


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5.6 Future State Mapping

Value stream mapping of the future state identifies the essential and non essential value added

activities in the process. The plant works on a continuous basis for 16 hours a day for complete

year except for major shutdowns and runs as 2 shift per day of 8 hours each. Figure 5.11 & 5.12depicts the future state mapping of value stream related to complete production process for cub-

frame and coolant channel respectively. Small boxes in the map represent the process and each

process has a data box below, which contains cycle time (CT), processing time (PT), changr over

time (C/O), machines and equipments (MAE), overall equipment efficiency (OEE), number of

operators (OP), number of shifts runs per day, production lead time (PLT) at each process. These

data were collected by personal observation in the shop floor and talking to operators at each

work station. The timeline at the bottom of the current state map has two components; first

component is non-value added (NVA) activity, which is sum of each inventory triangle before

each process. The NVA for one triangle is calculated by dividing the inventory quantity into

daily customer requirements. The lead time for one inventory triangle is calculated by dividing

the inventory quantity into the daily customer requirements. Operation wise analysis of NVA,

VA, WIP inventory and other critical aspects are discussed.

5.7 Advantages of Proposed Method

5.7.1 Advantages of the Proposed Method of cub-frame manufacturing

Drilling and tapping is completely removed in Sheet metal department. Cycle time will be reduced with the availability of the new process. Manual strain of the labors will reduced in assembly with the elimination of the drilling

and tapping.

Quality of the materials produced in sheet metal department will be improved withaccurate cutting of hole in the machines with the help of laser cutting machines.

Manufacturing cost is reduced because of implementing the new process. Wastage of the materials will be less designs of drilling holes will be given by the

designing department with that hole will be made according to the design.

Drilling problems like over sized or under sized drill will be eliminated with usage oflaser cutting machine.


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Labor cost also reduced and also highly skilled labors will be eliminated. Marking time for drill a hole will completely remove.

5.7.2 Advantages of the Proposed Method of coolant channel

manufacturing

Cycle time will be reduced with the new process of coolant channel manufacturing. Marking and machining of rectangular plate will be completely eliminated. Welding and automation in welding for new process is less because welding length will

be less compare to the old process and also the manufacturing time will be less.

Manufacturing cost of the component produced is less compare to old process becauseof the machining cost of the rectangular plate will be more compare to the circular bush

Wastage of the material will be completely eliminated with the help of circular threadedbush

Quality of the manufacturing component will more compare to the old process Highly skilled labors are not required

development of new sampling

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